The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
The present invention relates to fluid-mechanical and other electro-mechanical systems, more particularly to methods and apparatuses for ascertaining or assessing defects in such systems.
A pressurized fluid delivery system is a type of electro-mechanical delivery system. Pressurized fluid delivery systems normally include a pump (for water or other liquid) or compressor (for air or other gas), a conduit configured in plural sections, plural pressure switches and plural valves. Typically, when the system xe2x80x9csprings a leak,xe2x80x9d several pressure switches react to the drop in pressure, with the result that the entire system automatically shuts down. This total system shutdown is frequently an unnecessary and unwanted consequence of a single leak.
More generally, it is frequently undesirable for an electro-mechanical delivery system of any kind to unnecessarily shut down as a consequence of a single fault or defect, especially if such system can continue to operate in near-optimal fashion in spite of such fault or defect.
In view of the foregoing, it is an object of the present invention to provide method, apparatus and software for pinpointing a fault or defect in an electro-mechanical delivery system such as a pressurized fluid delivery system.
It is a further object of the present invention to provide such method, apparatus and software so that such system can avoid shutdown.
It is another object of the present invention to provide such method, apparatus and software so that such system can continue to operate, substantially as it had before the occurrence of the fault or defect, in circumventive fashion with respect to the fault or defect.
In accordance with many embodiments of the present invention, a processor-controller is associated with at least one combination (more typically, each combination) of a valve/switch and dual sensors, such combination being included in an electro-mechanical distribution system. The processor-controller processes information received from the sensors and controls the open-versus-closed actuation of the valve/switch. According to the inventive control logic, the valve/switch-sensor combination is either in normal mode or fault (defect) mode. When a fault condition of either sensor is detected, the processor-controller converts from normal mode to fault mode. A xe2x80x9ctransient waitingxe2x80x9d period takes place at the outset of the fault mode. Then, the control logic may either continue in fault mode by proceeding through a sequence of steps, or return to normal mode. In each step, a xe2x80x9cstep waiting periodxe2x80x9d (during which time the valve is closed) may be followed by a xe2x80x9cstep testing periodxe2x80x9d (during which time the valve is closed). While in normal mode, if at any time either sensor detects a fault condition, the control logic goes to fault mode; otherwise, the control logic remains in normal mode. While in fault mode, if at any time both sensors concurrently detect a normal condition, the control logic returns to normal mode; otherwise, the control logic remains in fault mode. When the inventive stepped control logic sequence is complete, the inventive practitioner realizes that the suspected fault associated with a given such combination is most likely real.
Many embodiments of the present invention provide apparatus for use in association with an electro-mechanical distribution system characterized by at least one branch, an entity (e.g., fluid or electrical current) for being distributed by said electro-mechanical distribution system to some degree by way of said at least one branch, at least one source of said entity, and at least one station for affecting distribution of said entity. The at least one station is in communication with the at least one branch. Each station includes switching means and a pair of sensing means on both sides of the switching means. The inventive apparatus is for isolating at least one fault condition within the electro-mechanical distribution system. The inventive apparatus comprises at least one machine having a memory. Each machine: is connected with a station; receives input from the corresponding pair of sensing means; effectuates control with respect to the corresponding switching means; contains a data representation of a stepped control logic scheme which defines the effectuating of control and which relates to the corresponding pair of sensing means and the corresponding switching means. The stepped control logic scheme includes a normal mode and a fault mode, wherein the indication of a fault condition by at least one of the corresponding pair of said sensing means at any time during said normal mode results in a change from said normal mode to said fault mode, and wherein the simultaneity of indication of a normal condition by both of the corresponding pair of said sensing means at any time during said fault mode results in a change from said fault mode to said normal mode.
Typically according to such inventive apparatus embodiments, the fault mode includes at least one step. Each step includes a pre-test waiting period and a testing period which follows the pre-test waiting period. During the pre-test waiting period the switching means is in a closed condition. During the testing period the switching means is in an open condition. If it does not occur at any time during the pre-test waiting period that both of the corresponding pair of sensing means simultaneously indicate a normal condition, the switching means is rendered in an open condition at the conclusion of the pre-test waiting period, wherupon the testing period commences. If it does not occur at any time during the testing period that both of the corresponding pair of sensing means simultaneously indicate a normal condition, the switching means is rendered in a closed condition at the conclusion of the testing period. If it occurs at any time during the pre-test waiting period that both of the corresponding pair of sensing means simultaneously indicate a normal condition, the switching means is rendered in an open condition at the conclusion of the pre-test waiting period, wherupon the normal mode resumes. If it occurs at any time during the testing period that both of the corresponding pair of sensing means simultaneously indicate a normal condition, the switching means remains in an open condition at the conclusion of the testing period, whereupon the normal mode resumes.
Also typical according to such inventive apparatus embodiments, the fault mode includes a transient test waiting period which precedes the first step. If both of the corresponding pair of sensing means simultaneously indicate a fault condition, the transient test waiting period commences. During the transient test waiting period the switching means remains in an open condition. If it does not occur at any time during the transient test waiting period that both of the corresponding pair of said sensing means simultaneously indicate a normal condition, the switching means is rendered in a closed condition at the conclusion of the transient test waiting period, whereupon the first pre-test waiting period commences.
Further typical according to such inventive apparatus embodiments, there are at least two sequential steps. Each sequential step except the last sequential step is followed by a pre-test waiting period of the succeeding sequential step. Beginning the second sequential step, each pre-test waiting period is longer than the preceding pre-test waiting period. Beginning the second sequential step, each testing period is shorter than the preceding testing period. According to many such inventive apparatus embodiments, the duration of the transient test waiting period, the durations of the pre-test waiting periods, and the durations of the testing periods, are based on the following inventive principles: The amount of time required for the switching means to be rendered in an open condition and for the system to stabilize is designated xe2x80x9coxe2x80x9d. The amount of time required for the switching means to be rendered in a closed condition and for the system to stabilize is designated xe2x80x9ccxe2x80x9d. An incremental period to be added onto each of o and c is designated xe2x80x9cmxe2x80x9d. The expression 2(c+m) is designated xe2x80x9cpxe2x80x9d, wherein p is equal to the value 2(c+m). The total number of sequential steps is designated xe2x80x9cnTxe2x80x9d. Each sequential step is designated the xe2x80x9cnxe2x80x9dth sequential step, wherein xe2x80x9cnxe2x80x9d corresponds to the sequential number of the sequential step. The pre-test waiting period of the xe2x80x9cnxe2x80x9dth sequential step will be equal to a value of no less than np and no greater than (n+1)p. The transient test waiting period will be equal to the value [(nT+1)c+m]. The testing period of the xe2x80x9cnxe2x80x9dth said sequential step will be equal to the value [(nTxe2x88x92n+1)c+m].
The present invention additionally provides a computer program product comprising a computer useable medium having computer program logic recorded thereon for enabling computer means to ascertain a state of defectiveness relating to a station in an electro-mechanical system for moving an entity (e.g., fluid or electrical current). The station affects the movement of the entity. The station includes the combination of switching means and two sensing means. The two sensing means are on opposite sides of the switching means. According to typical inventive computer program product embodiments, the computer program logic comprises: means for enabling the computer means to establish a normal mode and a fault mode; means for enabling the computer means to appreciate the indication of a normal condition by either of the two sensing means; means for enabling the computer means to appreciate the indication of a fault condition by either of the two sensing means; following the indication of a fault condition by at least one of the two sensing means at any time during the normal mode, means for enabling the computer means to effect a change from the normal mode to the fault mode; following the simultaneous indication of a normal condition by both the sensing means at any time during the fault mode, means for enabling the computer means to effect a change from the fault mode to the normal mode; means for enabling the computer means to establish at least one step in the fault mode; means for enabling the computer means to establish, in each step, a pre-test waiting period and a testing period which follows the pre-test waiting period; means for enabling the computer means to cause the switching means to be in a closed condition during the pre-test waiting period; and, means for enabling the computer means to cause the switching means to be in an open condition during the testing period. Typically, the computer program logic further comprises means for enabling the computer to confirm ascertainment of the state of defectiveness of the station. When there is an absence of simultaneous indication of a normal condition by both sensing means at any time during the testing period, at the conclusion of the testing period, if there is not a next step, the computer means confirms ascertainment of the state of defectiveness of said station.
Typically according to such inventive computer program product embodiments, when there is an absence of simultaneous indication of a normal condition by both sensing means at any time during the pre-test waiting period, the following occur: at the conclusion of the pre-test waiting period, the computer means causes the switching means to adjust to an open condition; the computer means dictates that the fault mode continue to exist; and, (iii) at the conclusion of the pre-test waiting period, the computer means dictates that the testing period of the same step commence. When there is an absence of simultaneous indication of a normal condition by both the sensing means at any time during said testing period, the following occur: (i) at the conclusion of the testing period, the computer means causes the switching means to adjust to a closed condition; (ii) the computer means dictates that the fault mode continue to exist; and (iii) at the conclusion of the testing period, if there is a next step, the computer means dictates that the pre-test waiting period of the next step commence. When there is simultaneous indication of a normal condition by both sensing means at any time during the pre-test waiting period, the following occur: (i) the computer means causes the switching means to be in an open condition at the conclusion of the pre-test waiting period; and, (ii) the computer means dictates that the normal mode exist, the computer means thereby dictating that the fault mode cease to exist. When there is simultaneous indication of a normal condition by both said sensing means at any time during said pre-test waiting period, the following occur: (i) the computer means causes the switching means to be in an open condition at the conclusion of the pre-test waiting period; and, (ii) the computer means dictates that the normal mode exist, the computer means thereby dictating that the fault mode cease to exist.
Further provided by the present invention is a method for recognizing at least one defective condition within an electro-mechanical system. The electro-mechanical system is of a kind which motivates an entity (e.g., fluid or electrical current) through at least one pathway of the system. The system has at least one station. Each station includes valvular means and two sensing means wherein the valvular means is generally interposed between the two sensing means. According to many such inventive method embodiments, with regard to a particular station the method comprises receiving information from each sensing means and regulating the switching means, wherein based on the received information the regulating is described by the following: The system is considered to be in either normal mode or defective mode. The defective mode includes an initial waiting period and a succession of plural steps. The initial waiting period precedes the succession of plural steps. Each step has a step waiting period and a step testing period. Within each step the step waiting period precedes the step testing period. As the succession of plural steps advances, the duration of each step waiting period increases. As the succession of plural steps advances, the duration of each step testing period decreases. During the normal mode, the valvular means is in an open position. During the initial waiting period, the valvular means is in a closed position. During each step waiting period, the valvular means is in a closed position. During each step testing period, the valvular means is in an open position. The normal mode ends and the defective mode begins as a consequence of the occurrence, at any time during the normal mode, of a defective condition pertaining to at least one sensing means. The defective mode ends and the normal mode begins as a consequence of the simultaneous occurrence, at any time during the defective mode, of a normal condition pertaining to both sensing means. The normal mode continues in the absence of the occurrence, at any time during the normal mode, of a defective condition pertaining to at least one sensing means. The defective mode continues in the absence of the simultaneous occurrence, at any time during said defective mode, of a normal condition pertaining to both sensing means. The defective condition is deemed fully recognized upon the completion of the final testing period of the defective mode.
The present invention is rooted in its appreciation that, if a leak in a pressurized fluid delivery system could be identified, isolated and circumvented, the pressurized fluid delivery system would thereby continue to operate with near-optimum efficiency. The present invention recognizes and fills a need in association with practically any electro-mechanical delivery system which is susceptible to occurrence of a fault or defect. This need is for a methodology which enables the electro-mechanical delivery system to continue operating substantially as intended in the absence of such fault or defect. The inventive methodology essentially involves or leads to identification, isolation and circumvention of such fault or defect.
The present invention provides a software-based methodology for automated damage reconfiguration of an electro-mechanical delivery system such as a pressurized fluid (liquid or gas) delivery systemxe2x80x94for example, a pressurized air delivery system. Featured by the present invention, inter alia, is a distributed control strategy which is effectuated in the absence of communications between valve controllers. Typical embodiments of the present invention effectuate distributed control: (i) in the absence of network communications; (ii) in the absence of location information; and, (iii) using identical software on each xe2x80x9cstation.xe2x80x9d
Generally, the inventive algorithm provides automated damage reconfiguration in the event of a fault in an electro-mechanical distribution system. The core idea used by the inventive algorithm is its stepped control logic. The present invention typically provides inventive control logic for damage reconfiguration of an electro-mechanical distribution system utilizing distributed control without network communications or location information and using identical software on each station (control unit). Notably, typical inventive embodiments provide automated damage reconfiguration without network communication in the event of a fault in an electro-mechanical distribution system.
The term xe2x80x9celectro-mechanical distribution systemxe2x80x9d refers to any distribution system which has indicia of both mechanical operation and electrical operation, wherein such system includes apparatus of an electrical and/or mechanical nature, and wherein such system has a purpose of moving an entity (such as fluid or electricity) in or through the system, typically for distributive purposes.
The term xe2x80x9cstationxe2x80x9d as used herein refers to any electrical, mechanical or electro-mechanical apparatus or combination of apparatuse located in the xe2x80x9ccircuitryxe2x80x9d of an electro-mechanical distribution system, wherein such apparatus has a terminal or gate-like function relating to control of the distribution of an entity (e.g., fluid or electricity) in or through the electro-mechanical distribution system, and wherein such device effectively or potentially represents a discontinuity or change in the movement (e.g., flow or transmission) of such entity in or through the electro-mechanical distribution system.
Typically, a noninventive xe2x80x9cstationxe2x80x9d includes: (i) circuit-breaking means, for xe2x80x9cbreakingxe2x80x9d a circuit (e.g., valvular means for breaking a fluid piping circuit, or electrical switch means for breaking an electrical circuit); and (ii) threshold-operating means, for determining the respective conditions (e.g., as pertains to a fault or defect) existing, in the circuity, adjacent to the circuit-breaking means on each of both sides of the circuit-breaking means.
For instance, a xe2x80x9cstationxe2x80x9d in a fluid distribution system can include a valve and a pair of pressure switches on either side of the valve, such as described herein in relation to a pressurized air delivery system used for inventive testing. A pressure switch is a device which converts presure change into an electrical function, and typically includes a diaphragm. A diaphragm is a membrane, made of flexible material, which is deflected by input pressure and thus represents the sensing element of a pressure switch. A sensing element is the portion of a pressure switch which is directly responsive to changes in input pressure. A xe2x80x9cstationxe2x80x9d in an electric distribution system can include, for instance, an electrical switch and an electrical measuring or sensing device (e.g., a voltmeter or ampmeter) on either side of the electrical switch.
According to typical embodiments of this invention, at least one xe2x80x9cnoninventive stationxe2x80x9d is inventively amplified so as to include not only a valve/switch and sensors, but to also include controller/processor means. In other words, the noninventive station is inventively amplified so as to include a grouping of a valve/switch, sensors, a controller and a computer chip. Such grouping effectively represents a unit which can be referred to as a control unit. In other words, according to typical inventive embodiments, a conventional (noninventive) station (which comprises a valve/switch and sensors) is rendered further inclusive so as to become an xe2x80x9cinventive station.xe2x80x9d The inventive station (or, synonymously as used herein, xe2x80x9cinventive control unitxe2x80x9d) includes a valve/switch, sensors, a controller and a computer chip. According to frequent inventive practice, then, the conventional station is placed in a functional relationship (and perhaps a structural relationship, as well) with controller/processor means (which typically, according to the present invention, includes a controller and a computer chip).
Although the inventive algorithm was tested on a compressed air distribution (pressurized air delivery) system with multiple branches, the inventive algorithm may be applied to other types of systems by altering the values used by the stepped control logic. In relation to a pressurized air delivery system, the inventive algorithm has been thoroughly tested and demonstrated using multiple branches with multiple faults and multiple service loads. The multiple faults were introduced simultaneously and in sequence during system reconfiguration. The faults were also introduced with service loads pre-existing and with additional service loads being added during system reconfiguration with additional faults being added during system reconfiguration. The sizes of both the individual faults and service loads were varied to simulate actual faults and loads.
The inventive algorithm provides damage reconfiguration, typically using low-cost components and computer chips having relatively small memories (processor speed must be appropriate for the system being reconfigured). Furthermore, the present invention avoids the use of networks, and installation and maintenance are simple. In the compressed air delivery system on which the inventive algorithm was tested, simple pressure switches (as opposed to pressure sensors) were used along with valve controllers that only implement two states, viz., open or closed (as opposed to continuously variable valve position controllers).
Inventive practice admits of greater refinement involving more advanced components. For instance, an inventive embodiment of a damage reconfiguration system using more advanced sensors and control valves would provide a greater level of sophistication; however, this kind of more refined inventive approach may not be preferable for many applications, since the cost of a more sophisticated system will often prove to be significantly greater than the cost of a less sophisticated system, especially if the system being automated is large. The present invention generally works quite well using less advanced sensors, the inventive algorithm handles calibration variances that tend to become greater in lower priced sensors.
According to typical inventive embodiments, to provide ease of installation and repair as well as system expansion or system layout changes, the inventive algorithm is identical on all nodes, and location information is not required. In contrast, according to some other, noninventive types of reconfiguration systems, individual stations must be programmed during installation with location data that indicates the specific location of the station in the overall system. In these other types of systems, the station will not perform its function properly without the location information. Therefore, installation and replacement of stations in these other types of systems involves programming in the location-specific data during installation and/or replacement of a station; expanding such a system to include additional stations or altering the layout of the system may involve a redesign of the algorithm pertaining to such system. By comparison, no location information is needed according to the present invention; because the inventive algorithm uses no location information, installation or replacement of stations or expansion or layout changes is simpler and less costly.
Network communications are not needed for proper functioning of the inventive algorithm. Therefore, the costs associated with network installation and maintenance can be avoided and network failures will not affect system performance. Nevertheless, the inventive algorithm tested on the compressed air system and described herein utilizes network communications for the sole purpose of demonstrating remote observation and manual override control capabilities; that is, this was only aimed to facilitate observation of system operation during presentations of the working system and to demonstrate the utility of manual override control. A network bus and a personal computer running human-machine interface (HMI) software were used. In inventive practice, the personal computer and the network are not necessary for correct functioning of the present invention""s autonomous damage reconfiguration algorithm; they can, however, be included in inventive embodiments in situations wherein system observation and/or manual override control are desired.
In accordance with the present invention, in the event of malfunction of one or more stations, the remainder of the inventive system will continue to function correctly. Each station performs its function as a stand-alone device. Because the stations do not communicate with one another, their proper functioning will not be affected by the behavior of other stations.
The inventive automated damage reconfiguration system described herein is uncomplicated, effective and relatively inexpensive to install and maintain. No network is required, thus avoiding costs associated with network installation and maintenance. No location information is needed, thus reducing costs associated with installation, replacement and system expansion. According to many inventive embodiments the inventive algorithm is simple and small, therefore allowing use of relatively small (in terms of memory), lower priced computer chips at each station. The inventive algorithm typically uses only two simple, low cost sensors at each station. The sensors need not adhere to strict calibration requirements. Generally, for a compressible fluid distribution system (liquid or gas distribution system), the required sensors are low cost pressure switches.
An inventive software prototype was installed and thoroughly tested on a full scale U.S. Naval Destroyer model of a low-pressure air delivery system. Singular and multiple leaks were successfully isolated, and multiple leaks were introduced simultaneously and sequentially. The inventive software distinguished between leaks that dropped the pressure below a set threshold and loads that did not. Further, no oscillations occurred when slow leaks were introduced.
A preferred embodiment of the inventive software, such as that used for U.S. Navy testing, includes a stepped control scheme that uses timing which depends on system parameters such as the speed of the valve actuators, the system volume, the number of sources and the supply pressure. The inventive testing proved successful; during the testing, only the valves directly adjacent to the leak remained closed and no other valves remained closed erroneously. Each and every valve controller contained the identical inventive software. Location information was not used, since no network communication was used between the Neuron Chips in this system.
The methodology according to this invention allows for successful automatic reconfiguration of the electro-mechanical system in the event of a network failure. The invention accomplishes automated damage reconfiguration of an electro-mechanical system (e.g., a pressurized air delivery system) via a distributed control scheme and without communications between/among the controllers (e.g., valve controllers). According to many inventive embodiments, the program also responds to xe2x80x9cmanual override openxe2x80x9d, xe2x80x9cmanual override closedxe2x80x9d and xe2x80x9creset and return to automatic modexe2x80x9d commands from human-machine interface (HMI) software running on a separate processor.
The automated damage reconfiguration algorithm in accordance with the present invention is both simple and effective. At the heart of this invention is its stepped control logic. A network is not needed for autonomous damage reconfiguration, and no location information is required. The inventive algorithm is typically designed for use with low-cost sensors, two state gate controllers and computer chips with relatively small memory. The inventive algorithm is designed to handle multiple branches, multiple service loads and multiple faults. The inventive algorithm has been thoroughly tested on a compressed air distribution and may be applied to any electro-mechanical distribution system.
Installation and maintenance associated with the present invention are relatively simple. The inventive algorithm handles sensor calibration variances, and its operation may be remotely observed and manually overridden using a network bus and a personal computer running man-machine interface software. Additionally, if one or more inventive stations (inventive control units) fail, the remainder of the system continues to function properly. The inventive algorithm may be applied as a backup algorithm to a damage reconfiguration system algorithm that uses network communications. In the event of a network failure the inventive control algorithm could stop using the algorithm requiring network communications, and begin using an inventive control algorithm based on the inventive stepped control algorithm so that the system would reconfigure if system damage occurred.
The component which has a sensing element on each side is generically referred to herein as a xe2x80x9cvalve/switchxe2x80x9d or xe2x80x9cvalvular/switching meansxe2x80x9d or xe2x80x9cswitching meansxe2x80x9d or xe2x80x9cvalve meansxe2x80x9d or xe2x80x9cvalvular means,xe2x80x9d wherein such terms are intended to be synonymous. Each term is intended to denote any valve-like or switch-like device which accomplishes a similar purpose of regulating or changing flow or transmission of an entity which is passable therethrough, as by connecting, disconnecting, diverting, transferring, increasing apertural size, decreasing apertural size, adjusting apertural configuration, opening, closing, beginning operation, ceasing operation, etc. The xe2x80x9csensing elementxe2x80x9d on opposite sides of the switching means is intended to denote any sensing device which can accompany such switching means, such as that which includes a pressure sensor, a voltage sensor (e.g., voltmeter), current sensor (ampmeter), etc.
The inventive methodology is based on a stepped control logic sequence which is adaptable to different system types, sizes and architectures. This adaptibility can be accomplished by changing, adjusting or otherwise appropriately setting the values used by the inventive stepped control logic. According to typical inventive embodiments, the inventive stepped control logic algorithm is entered when the sensing elements (e.g., pressure sensing, voltage sensing, current sensing, etc.) on each side of a valve/switch indicate a fault condition, and the fault condition has been determined to not be transient. The stepped control logic algorithm is exited and the valve/switch opens if the sensing elements on each side of the valve/switch indicate a normal condition.
Response to transient fault conditions is avoided through the use of a waiting period. Each step of the inventive control logic includes a waiting period followed by a testing period. According to many inventive embodiments, initially a special kind of waiting period referred to herein as a xe2x80x9ctransientxe2x80x9d waiting period takes place. At the outset of the present invention""s control logic sequence, when a fault condition is detected by the two sensing elements, the transient waiting period begins. If the end of this transient waiting period is reached and the sensing elements on each side of the valve/switch indicate a faulty condition throughout the transient waiting period, then the inventive algorithm causes the valve/switch to close and continues to the first step of the control logic. If the end of the transient waiting period is reached and the sensing elements on each side of the valve/switch do not indicate a fault condition throughout the waiting period, the valve/switch remains open and the first step of the inventive stepped control logic algorithm is not entered. If the sensing elements on each side of the valve/switch all indicate a simultaneous normal condition at any time during the transient waiting period, the transient waiting period is terminated, the valve/switch remains open, and the first step of the present invention""s stepped control logic algorithm is not entered.
Each xe2x80x9cstepxe2x80x9d of the inventive stepped control algorithm includes two time periods, viz., a xe2x80x9cpre-test waiting periodxe2x80x9d and a xe2x80x9ctesting periodxe2x80x9d which follows the pre-test waiting period. The pre-test waiting periods all share similar attributes. The testing periods, as well, all share similar attributes. In fact, according to inventive embodiments providing for an initial xe2x80x9ctransientxe2x80x9d waiting period precedent to the first step, the transient waiting period is analogous to each step""s pre-test waiting period. In particular, if at any time during the waiting period there is simultaneity of normal condition indication by both sensing elements (i.e., there is absence of fault condition indication by at least one sensing elemement), at the conclusion of such waiting period the inventive algorithm switches from xe2x80x9cfault modexe2x80x9d to xe2x80x9cnormal mode,xe2x80x9d according to which the valve/switch either remains in an open condition (in the case of the conclusion of a xe2x80x9ctransientxe2x80x9d waiting period) or changes to an open condition (in the case of the conclusion of each xe2x80x9cpre-testxe2x80x9d waiting period).
The same inventive principal applies to the testing periods. In other words, if there concurrence by both sensing means of normalcy indication at any interval during either (i) a waiting period (whether a xe2x80x9ctransientxe2x80x9d waiting period or a step""s xe2x80x9cpre testxe2x80x9d waiting period) or (ii) a testing period, the inventive stepped control logic exits fault mode and enters normal mode. The absence of such concurrence results in the inventive stepped control logic moving on to the next stage or time period in the sequential scheme.
According to typical inventive practice, among the properties of the waiting period are the following: The waiting period is a time period which is not considered to have begun until a supply exists on one side of the valve/switch. The waiting period may be based on a limited random delay.
According to typical inventive practice, among the properties of the testing period are the following: The testing period is a time period during which a test is performed on the integrity of the system section isolated by the switch. The test comprises opening the valve/switch for a period of time and observing the sensing elements on either side of the valve/switch. If the end of the testing period is reached and the sensing elements do not indicate a normal reading, then the valve/switch should return to the closed position, and the algorithm should move on to the next step in the testing sequence.
The present invention""s control logic may comprise one or more steps. Each progressive (or succeeding) step has a longer waiting period and a shorter testing period. According to many inventive embodiments, these periods may be based essentially on the following: First, determine the time required for the gate to open and the system to stabilize and call this value xe2x80x9coxe2x80x9d. Subsequently, determine the amount of time required for the gate to close and the system to stabilize and call this value xe2x80x9ccxe2x80x9d. Subsequently, determine an appropriate amount of time to be used as a slight additional margin to be added on to xe2x80x9coxe2x80x9d and xe2x80x9ccxe2x80x9d and call this value xe2x80x9cm.xe2x80x9d Subsequently, set the stepped control logic values as follows: Set the step 1 pre-test minimum waiting period to a value greater than 2(c+m) and call this value p. The step one pre-test maximum waiting period will thus be 2p. The step two pre-test minimum waiting period will be 2p, and the step two pre-test maximum waiting period will be 3p. The step three pre-test minimum waiting period will be 3p, and the step three pre-test maximum waiting period will be 4p. The transient test waiting period will be 4c+m. The step one gate-open test period will be 3c+m. The step two gate-open test period will be 2c+m. The step three gate-open test period will be c+m. The gate-open test length (if used) within the fault isolation mode will be o+m.
In inventive practice, the values for m and p may need to be determined experimentally for a given system. The number of steps may need to be increased in systems with a large number of branches.
The present invention has been thoroughly tested on a compressed air distribution system. Installation and maintenance is relatively simple. The inventive algorithm handles sensor calibration variances, and its operation may be remotely observed and manually overridden using a network bus and a personal computer running man-machine interface software. Additionally, if one or more stations fail, the remainder of the system continues to function properly. The present invention""s stepped control logic is adaptable for reconfiguration of almost any electro-mechanical distribution system.
If the current trend in the U.S. Navy continues it can reasonably be expected that, compared to today, Naval ships of the future will be much more highly automated and have significantly reduced manning, and thus will be much more heavily dependent upon automated network systems to replace sailors aboard ship. Perhaps future Naval ships will be endowed with the present invention, and beneficially so, the present invention""s innovative software potentially represents the xe2x80x9cfailsafexe2x80x9d of these networked mechanical and electrical systems that are vital to a ship""s survival.
The automated damage reconfiguration system may be applied to electrical distribution systems, including power grids and communication systems. In such systems, the inventive xe2x80x9cstationxe2x80x9d (also referred to herein as the inventive xe2x80x9ccontrol unitxe2x80x9d) may comprise an electrical switch, a switch controller, a computer chip and voltage or current sensors on either side of the electrical switch. An electrical distribution system may use voltage sensors to determine the existence of a suitable source voltage on either side of the inventive station while the electrical switch is in an open state. While the electrical switch is in the closed state, the voltage sensors may be used to measure the voltage on either side of the inventive station and determine a fault condition when the voltage drops or rises to a value outside of a pre-determined range. Current sensors may also be used to determine that a fault condition exists when the current exceeds a certain limit. Using such equipment, any faulty branch of the system would become isolated without the expense of a network wiring installation.
The non-network dependent damage reconfiguration control logic discussed herein may be used as a backup algorithm for a damage reconfiguration system that normally uses network communications. In the event of a network failure the software may switch from xe2x80x9cnetwork communicationxe2x80x9d mode to a xe2x80x9cnetwork failurexe2x80x9d mode which uses the non-network damage reconfiguration control logic. To determine whether the network is intact, a network token may be passed from one control unit to another in a predetermined order. As each inventive station passes the token on, a timer may be started, and if the token is not returned within a predetermined amount of time it will assume that a network failure exists. The algorithm will then change from xe2x80x9cnetwork communicationxe2x80x9d mode to a xe2x80x9cnetwork failurexe2x80x9d mode and use the inventive xe2x80x9cstepped control logicxe2x80x9d to perform damage reconfiguration when necessary. Thus the damage reconfiguration system that normally uses network communications will continue to function in the event of a network failure. This method was successfully used in the compressed air system on which the inventive algorithm was tested. When a network failure occurred, each inventive station changed from xe2x80x9cnetwork communicationxe2x80x9d mode to xe2x80x9cnetwork failurexe2x80x9d mode and the faulty sections of the pressurized air system were successfully isolated.
The accompanying drawings contain flowcharts which lend visual explanation to the inventive software. Appended hereto is the present invention""s actual Neuron C program which was used in U.S. Navy testing. The algorithmic program contained in APPENDIX A and the flowcharts pertaining thereto are written in the event-driven language xe2x80x9cNeuron Cxe2x80x9d which is used by the Neuron Chip made by Echelon Corporation. The present invention""s flowcharts and algorithm represented herein may be adapted to any platform with the appropriate alterations; in the light of this disclosure, the ordinarily skilled artisan will be capable of practicing diverse embodiments of the present invention, including effectuating diverse inventive adaptations.
Other objects, advantages and features of this invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
The following appendices are hereby made a part of this disclosure:
Attached hereto marked APPENDIX A and incorporated herein by reference is an embodiment of a Neuron C computer program in accordance with the present invention. This computer program contains an inventive algorithm for automated damage reconfiguration using stepped control logic. This program enables the valves in a low pressure shipboard pressurized air delivery system to isolate leaks automatically. This program is also designed to communicate with a specific man-machine interface (MMI) program.